As we ride the wave of revitalized pearl jewelry, the ocean-born gem continues to reveal its range. We look beyond the iconic classic white strands favored by socialites and celebrities and explore even more elusive, vibrant variants. Here’s a quick-hitting guide to some of the planet’s rarest, most cherished pearls.

Conch Pearls

The Pearl: Conch (pronounced konk) pearls are petite, vivid gems that come from queen conch sea snails, which live in the Caribbean Sea off the coasts of the Bahamas and into the Gulf of Mexico.

The Color: Their colors range from peach to pastel pink—dark pink is the rarest and most coveted. Conch pearls are consistently petite, typically the size of a seed pearl or small flower bud.

How Rare? Extremely. About 1 in 10,000 queen conch sea snails produces a conch pearl, and just one in 100 is of gem quality. Accordingly, good-quality conch pearls have a probable occurrence of one in a million. Moreover, the queen conch does not respond well to culturing efforts. Devoted designers who want to craft a conch pearl piece often scour estate sales and antique fairs for years to find examples. A complete design with pearls of a consistent color and size (like the Lugano earrings below) often takes decades—or even a lifetime—to produce.

Tahitian Black Pearls

The Pearl: These alluring dark pearls come from the black-lipped oyster, which resides in the temperate turquoise waters off French Polynesia. In contrast to other pearls, these skew larger, typically from 8 mm up to 18 mm, ranging from the size of a petit pois to a large grape. All are ideally shaped for a stunning statement ring or a bold, modern necklace.

The Color: Tahitian black pearls actually encompas a whole palette of colors, including dark green and peacock—a tone that is an enigmatic iridescent blend of blues and greens. While the subtle hues of each example may vary, the black pearl’s effect is unfailingly dramatic.

How Rare? Very. Only black-lipped oysters produce these alluringly dark pearls, and while many are farmed near the Cook Islands, Micronesia, and Japan, only those from French Polynesia can officially produce the coveted Tahitian black pearl (see design from YOKO London shown below).

Melo Melo Pearls

The Pearl: Melo melo pearls are produced by the melo melo sea snail, which can be found in Southeast Asia—specifically, the South China Sea, the Gulf of Thailand, the Andaman Sea, and the Bay of Bengal near Burma. Though its natural shape is generally spherical, a robustly rounded melo melo pearl of significant size (like the one in the pendant design below by Assael) is hard to find.

The Color: The gem’s intense tone encompasses an array of hues, from a fiery orange to a pale, marbled yellow. Pearly marbling on the melo melo is common—it’s also referred to as “flames”—so the rarest examples have a pure, deep color. Take special care of the melo melo; its color has been known to fade with sun exposure.

How Rare? It is estimated that only one in every several thousand melo melo sea snails produces a pearl of notable size. And the chance of procuring a gem with a perfectly peachy hue is even slimmer.

Golden South Sea Pearls

The Pearl: Golden South Sea pearls are made by the golden-lipped oyster, which lives in the azure waters surrounding the Philippines. The golden pearl is among the largest on the market, on average growing to 13 mm—about the size of a raspberry.

The Color: Pale, sunny yellow to honey amber. The most desirable golden South Sea pearls boast a deep golden hue.

How Rare? In addition to the fact that only golden-lipped oysters can produce the gem, it takes the creature at minimum 3 years to generate a golden pearl. But the results, displayed in the designs by Jewelmer and Mikimoto below, are breathtaking.